Mechanism for the step-by-step transport of documents

ABSTRACT

Apparatus for advancing a record medium step by step wherein the medium is advanced by a drive wheel mounted on a shaft to which is affixed a ratchet wheel, wherein the ratchet wheel is advanced tooth by tooth by an actuating pawl, and wherein said pawl moves into engagement with the ratchet wheel and rotates the ratchet wheel through one tooth pitch by the action of respective ones of a pair of cams.

[56] References Cited UNITED STATES PATENTS 6/1967Blodgett.......................

Jacques Roland Deproux Sevres, France 3,097

[211 App]. No. [22] Filed OTHER REFERENCES IBM Technical DisclosureBulletin, Vol. 4, No. 2, pg. 18, July 1961, published by internationalBusiness Machines Corporation, New York, NY.

Jan. 15, 1970 [45] Patented Dec. 21, 1971 [73] Assignee Societelndustrlelle Honeywell Bull [32] Priority Jan. 29, 1969 [3 3] France [311 6901792 Primary Examiner-Allen N. Knowles Assistant Examiner-Gene A.Church AttorneysFred Jacob, Ronald T. Reiling and Lewis P.

Elbinger 54] MECHANISM FOR THE STEP-BY-STEP TRANSPORT OF DOCUMENTS 8Cllllll, 3 Drawing Figs.

ABSTRACT: Apparatus for advancing a record medium step 74/125 by stepwherein the medium is advanced by a drive wheel B6511 17/22 [51] Int.mounted on a shaft to which is affixed a ratchet wheel, [50] Field of226/157, wherein the ratchet wheel is advanced tooth by tooth by anactuating pawl, and wherein said pawl moves into engagement with theratchet wheel and rotates the ratchet wheel through one tooth pitch bythe action of respective ones of a pair of cams.

BACKGROUND OF THE INVENTION The present invention relates toimprovements in transport mechanisms for advancing documents step bystep in punched card or similar machines and concerns more particularlyimprovements in the mechanisms used for advancing cards or tapes inrecording mechanisms such as punches or for advanc- 1 ing line by lineone or more strips or sheets of paper in a high- 0 speed printer.

Punching machines are known which operate column by column, in therecording of cards or tapes, and capable of normal operation at the rateof I60 to 200 perforation cycles per second. These known devices,mechanical, hydraulic, electromagnetic, and others, using step-by-stepadvancement of documents, are not generally adapted for correct andprolonged operation at such speeds.

The object of the present invention is to remedy these inconveniencesand provide an improved mechanism for stepby-step advancement, which isprecise, sturdy, and of a relaconditions of utilization.

SUMMARY OF THE INVENTION A transport mechanism in accordance with theinvention comprises a secondary shaft with a ratchet wheel, a primaryshaft moved by a motor in continuous rotation, carrying on one extremitya first cam and a second cam, a pawl-driving lever, wherein the pawl isnormally disposed in cooperative relationship with the teeth of theratchet, and a control electromagnet adapted to be energized forrendering the pawl inoperative. This mechanism is characterized by thefact that the pawl-driving lever has one extremity hinged on the sameaxle of rotation as the aforesaid ratchet wheel for step-by-stepdriving, and carries on a common axle of articulation a rubber rollerand a pawl lever, one arm of the latter bearing a contact fingeropposite to the corresponding first cam, and said pawl proper comprisinga tip adapted for engaging the trapezoidal intertooth regions of theaforementioned ratchet wheel. The body of the pawl comprising a slidingface opposite to said tip and of cylindrical form. The controlelectromagnet comprises pole pieces similarly of cylindrical form, whichare disposed in such a way that when the electromagnet is energized, thetip of the pawl cannot be engaged in the ratchet teeth, while continuingits circular reciprocating movement which is imparted by the drivinglever.

A mechanism constructed according to the present invention permits, whenit is associated with an identical mechanism, the realization of astep-by-step transport apparatus in which the speed of advance isdoubled, but in which the different elements nevertheless remain usefulunder normal conditions of operation, preserving a normal resistance towear, coupled with a great precision and absolute security of operation.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTIn the mechanism represented schematically, and only in part, in FIGS. 1and 2, a record card 1 to be driven step by step, for example, in ahigh-speed punching mechanism, is gripped on an edge between a movableroller 2 and a driving disk 3. Disk 3 is fixed to a secondary shaft 4which is driven step by step by the mechanism.

A similar arrangement may be provided for driving the card by theopposite edge. The advancement and the halting of the card in theapparatus may be controlled in a known manner by means of roller 2,according to whether the roller is pressed against or removed fromdriving disk 3. Shaft 4, as will be described later, may be driven byone or the other of two ratchet wheels 5 and 6, mounted on a hub 17keyed to shaft 4, these two wheels eachbeing able to be actuatedalternatively by a pawl. A pawl-driving lever 7 is mounted to be able tooscillate on shaft 4. This lever is provided with two bearings 8 and 9in which can oscillate a common axle of articulation 10 on which iskeyed to one end, a pawl 11A, and to the other end, a pawl lever 12. Thelatter is provided with a contact finger 13 disposed to be urged by aspring 16 against the periphery of a first cam 14. Cam 14 is fixed to aprimary shaft 15, which is driven in a continuous rotation in the senseof the arrow F, under the action of a motor not shown. A rubber roller20 is mounted to turn freely on the common axle of articulation l0 andit is constantly urged, similarly under the action of spring 16, againstthe periphery of a second cam 21, which is driven in rotation, as cam14, by primary shaft 15. In order to clarify the drawing, the outlinesof shaft 15 and of cams 14 and 21 have been represented only by mixeddashes in FIG. 2.

When shaft 15 is rotating, the action of cam 21 on roller 20 imparts todriving lever 7 an oscillatory movement in the course of which pawl llAdrives ratchet wheel 5 in a step-bystep rotational movement underconditions which will later be described more precisely. Through theoscillatory movement of lever 7, pawl 11A is animated with areciprocating movement in front of the fixed pole pieces 22 and 23 ofelectromagnet 24.

On the side opposite pawl 11A, the pole pieces of the electromagnet havethe form of a portion of a cylinder of which the axis is located on theaxis of shaft 4. Pawl HA is provided with a sliding face 25 of similarcylindrical form and disposed in such a fashion that when theelectromagnet is energized, the sliding face of the pawl is caused bymagnetic attraction to rub against a support block 26 affixed to thepole pieces and projecting slightly from between the latter. This blockis constituted of a nonmagnetic material, preferably self-lubricating.In this manner, when the electromagnet is energized, the pawl 11A isattracted and rotates lever 12 with its contact finger, which istherefore held away from cam 14 as long as tip 27 of the pawl is heldout of engagement with the teeth of ratchet wheel 5. Thus, ratchet wheel5 is prevented from being driven by the pawl so long as electromagnet 24is energized.

In FIG. 3, the curve C21 indicates the movements of the tip 27 of thepawl between an advanced position AV and a rearward position AR alongthe periphery of ratchet wheel 5 under the action of cam 21 in thecourse of a cycle of advance of the ratchet. The curve C14 indicates themovements of the tip of the pawl between an engaged position EG and adisengaged position DG with the teeth of the ratchet wheel, under theaction of cam 14, when the penetration movements of the pawl into theratchet wheel are not prevented by energization of electromagnet 24.

In the example described, cam 21 (FIG. 1) is provided with two bosses inorder to reduce the velocity of rotation of shaft 15; i.e., a cycle ofadvance of the pawl is efi'ected for each half-tum of the shaft. Hence,in FIG. 3, a cycle of movement of the pawl is indicated for a rotationof of motor shaft 15.

In FIGS. 1 and 2, the position of the different members of the apparatuscorrespond to the indicated 25 position on the diagram of FIG. 3,wherein the pawl is substantially in the middle of its course ofadvancement. Ratchet wheel 5 is represented in FIG. 1 as comprising 60teeth, with a tooth pitch I on the wheel corresponding to an angle a of6. However, the amplitude of oscillatory movement imparted to the pawlis slightly greater than 6 in order for the pawl to be driven back intoa rearward position from which it can descend behind the following toothwithout touching it.

In order to furnish an indication of the dimensions of the devicerepresented in FIG. 1 and 2, it is to be recalled that this device isfor advancing column by a column a record card, in which the standarddimensions between two successive columns is 2.21 millimeters. Sinceratchet wheel 5 is provided with 60 teeth, a card is advanced through 60columns by one revolution of driving disk 3 for which the radius R is21. 10 millimeters.

The operation of the apparatus will now be described with reference tothe diagram of FIG. 3. Considering a point, chosen as a reference fordeparture. At this moment the tip 27 of pawl 11A is engaged in the teethof the ratchet wheel (level EG of curve 0-14), and after a slight delaythe pawl is brought into contact with a tooth of the wheel, which isthen driven by said pawl with a movement first accelerating and thendecelerating, until the 50 point (curve C21) where the wheel halts. Atthe 25 point in the cycle, the ratchet wheel and all parts of theapparatus to which it is afi'rxed are being thrust forward with amaximum velocity which corresponds to the maximum slope of curve C21 atthis point in the cycle. In order to obtain the precise positioning of adocument and the halting of all the parts driven by the pawl withoutshock, such pawl must follow the rule of deceleration which is imposedon the pawl by cam 21, the form of the latter being provided to halt thepawl, without shock, at the 50 point in the cycle. To effect this, themechanism is provided with a frictional device in which the action isregulated to be sufficient to obtain the desired result. This brakingdevice comprises a rubber ring 30, which is attached to a fixed wall 31of the mechanism, and against which disk 3 is urged by a force FRexerted axially on shaft 4 of the mechanism by an appropriate means, forexample, by a spring which is not shown. From the 50 point to the 140point of the cycle, the pawl is drawn back to its rearward position(until at level AR of curve C21). It is only starting at the 55 pointthat the tip of the pawl commences to disengage from the ratchet teeth,that is, after the aforementioned pawl is clearly removed from the sideof the tooth which it has completed pushing. Under these conditions, thedisengagement of the pawl is effected from the 5 point to the 90 pointwithout any rubbing of the pawl against the tooth of the ratchet. Thepawl is then held in position disengaged from the teeth (level D6 ofFIG. 3) from the 95 point to the 140 point, whereupon it is engaged anewfrom the 140 point to the 180 point, again without rubbing against theteeth. Then a new cycle commences.

The advancement mechanism comprises two similar pawl mechanisms coupledto shaft 4 so that there can be obtained an advancement velocity fordocuments double that which can be obtained with a single mechanism.FIG. 2 shows only a part of the second mechanism. In the exampledescribed, this mechanism is of construction which is symmetrical to thefirst mechanism. This arrangement is advantageous for the machining ofratchet wheels 5 and 6, which are both affixed to hub 17; however, apawl mechanism identical to the first can be disposed on shaft 4. Theactuating cams of the second pawl mechanism are also mounted on primaryshaft 15, but these cams are displaced angularly 90 relative to the camsof the first mechanism. In FIG. I there is represented by mixed dashes acam 21B disposed for actuating pawl 118 (FIG. 2), mounted on axle 108,which is able to oscillate in the bearings of a pawl driving lever 78.Cam 21B is comprised, as is cam 21, of two bosses which are displaced by90 with relation to the bosses of cam 21. The second pawl is broughtinto engagement with its ratchet wheel, from the 50 point to the 90point of the cycle (FIG. 3) and then is advanced from its rearwardposition to its advanced position from the 90 point to the 140 point,while the first pawl is held in the disengaged position. Thus, while thefirst pawl is disengaged, a tooth is advanced a step under it by thesecond pawl, after which the first pawl is engaged (FIG. 3) from the 140point to the 180 point while the second pawl is disengaged (with a delayof 5). Next, the ratchet wheel is advanced a step from the 0 point (180)to the 50 point while the second pawl is in the disengaged position.Under these conditions, shaft 4 is halted from the 50 point to the pointand from the point to the 180 point, during which are permitted tworecording operations (punching) T1 and T2 per cycle, the document beingad vanced during the intervals AVl and AV2. The cams being doubled, eachpawl mechanism effects two cycles per revolution of shaft 15 and thecombined function of the two mechanisms furnishes four advancement stepsand four halted periods for recording for each revolution of shaft 115.Because of this, in a card punching machine operating at the rate ofcycles per second, the rate of rotation of primary shaft 15 is only2,400 revolutions per minute.

A mechanism according to this invention presents great flexibility ofemployment by the fact that at any moment the advance of a document canbe halted or reestablished by energizing simultaneously the twoelectromagnets 24 and 24B and then deenergizing them. The velocity ofadvance of a document can also be reduced by half by energizing only oneor the other of the two electromagnets.

It is evident that the example described is in no way limiting and thatall modifications and adaptations can be drawn from the describedarrangement, according to the situation and application, withoutdeparting from the invention.

I claim:

l. A transport mechanism for advancing a card or tape step by stepcomprising:

a secondary shaft having a ratchet wheel,

a primary shaft moved by a motor in continuous rotation,

carrying on one extremity a first cam and a second cam,

a pawl-driving lever,

a pawl normally disposed in cooperative relation with the teeth of theratchet,

a control electromagnet adapted to be energized for rendering the pawlinoperative,

one extremity of said pawl driving lever being mounted for rotation onsaid secondary shaft,

said pawl driving lever carrying a friction roller and a pawl lever on acommon axle of articulation,

an arm of said pawl lever bearing a contact finger opposite to saidfirst cam,

the pawl proper comprising a tip adapted for engaging in the trapezoidalintertooth regions of said ratchet wheel and the body of said pawlcomprising a sliding face opposite to said tip and of cylindrical form,

said control electromagnet comprising pole pieces similarly ofcylindrical form, which are disposed in such a way that when theelectromagnet is energized, the tip of the pawl cannot be engaged in theratchet teeth, while the pawl continues its circular reciprocatingmovement which is imparted to it by the driving lever.

2. A transport mechanism according to claim I, wherein the cam faces ofthe two cams are arranged such that after efiecting a driving step, thedriving lever draws back the pawl toward the rear before the movement ofdisengagement from the intertooth regions has been imparted to the tipof the pawl.

3. A transport mechanism for advancing a card or tape step by stepcomprising two transport mechanisms as set forth in claim 1, whereinsaid primary shaft carries a pair of cams, wherein the secondary shaftcarries two ratchet wheels, and wherein the cam pairs are orientedangularly in such a manner that the movements of advancement effected bythe two transport mechanisms when both are operating are out of phase byhalf of the duration of a driving cycle.

4. A transport mechanism for advancing a card or tape step by stepcomprising two transport mechanisms as set forth in claim 2, whereinsaid primary shaft carries a pair of cams,

wherein the secondary shaft carries two ratchet wheels, and wherein thecam pairs are oriented angularly in such a manner that the movements ofadvancement effected by the two transport mechanisms when both areoperating are out of phase by half of the duration of a driving cycle.

5. Apparatus for advancing a medium step by step comprisa drive wheelfor gripping said medium and rotatable for moving said medium,

a first rotatable shaft having a ratchet wheel and coupled to said drivewheel,

a second shaft adapted to be rotated and having a pair of cams, thebosses of said cams being angularly displaced,

a pawl-driving lever rotatable about the axis of said first shaft,

a third shaft rotatably supported at one extremity of said pawl drivinglever,

a pawl mounted on said third shaft and disposed to engage the teeth ofsaid ratchet wheel,

a first cam follower member mounted on said third shaft and urged tofollow one of said cams, whereby said pawl is controlled to cyclicallyengage the teeth of said ratchet wheel, and

a second cam follower member mounted to drive said pawldriving lever andurged to follow the other one of said cams, whereby said pawl iscontrolled to reciprocate along the periphery of said ratchet wheel.

6. The apparatus of claim 5 further including an electromagnet memberselectively energizable for attracting said pawl from engagement withsaid ratchet wheel.

7. A mechanism employed with step-by-step document transport equipmentcomprising in combination:

a pair of cams adapted to be rotated, the bosses of said cams beingangularly displaced,

a wheel having teeth uniformly disposed along the periphery thereof,

a shaft mounted for rotation,

a pawl mounted on said shaft and disposed to engage the teeth of saidwheel,

a first cam follower member mounted on said shaft and urged to followone of said cams, whereby said shaft is controlled to oscillate aboutthe axis thereof and thereby actuate said pawl to cyclically engage theteeth of said wheel, and

a second cam follower member coupled to said shaft and urged to followthe other one of said cams, whereby said shaft is controlled tooscillate transversely to said axis thereof, and thereby actuate saidpawl to reciprocate along the periphery of said wheel.

8. The mechanism of claim 7 further including an electromagnet memberselectively energizable for attracting said pawl away from engagementwith said ratchet wheel.

lOlOlS 0l30

1. A transport mechanism for advancing a card or tape step by stepcomprising: a secondary shaft having a ratchet wheel, a primary shaftmoved by a motor in continuous rotation, carrying on one extremity afirst cam and a second cam, a pawl-driving lever, a pawl normallydisposed in cooperative relation with the teeth of the raTchet, acontrol electromagnet adapted to be energized for rendering the pawlinoperative, one extremity of said pawl driving lever being mounted forrotation on said secondary shaft, said pawl driving lever carrying afriction roller and a pawl lever on a common axle of articulation, anarm of said pawl lever bearing a contact finger opposite to said firstcam, the pawl proper comprising a tip adapted for engaging in thetrapezoidal intertooth regions of said ratchet wheel and the body ofsaid pawl comprising a sliding face opposite to said tip and ofcylindrical form, said control electromagnet comprising pole piecessimilarly of cylindrical form, which are disposed in such a way thatwhen the electromagnet is energized, the tip of the pawl cannot beengaged in the ratchet teeth, while the pawl continues its circularreciprocating movement which is imparted to it by the driving lever. 2.A transport mechanism according to claim 1, wherein the cam faces of thetwo cams are arranged such that after effecting a driving step, thedriving lever draws back the pawl toward the rear before the movement ofdisengagement from the intertooth regions has been imparted to the tipof the pawl.
 3. A transport mechanism for advancing a card or tape stepby step comprising two transport mechanisms as set forth in claim 1,wherein said primary shaft carries a pair of cams, wherein the secondaryshaft carries two ratchet wheels, and wherein the cam pairs are orientedangularly in such a manner that the movements of advancement effected bythe two transport mechanisms when both are operating are out of phase byhalf of the duration of a driving cycle.
 4. A transport mechanism foradvancing a card or tape step by step comprising two transportmechanisms as set forth in claim 2, wherein said primary shaft carries apair of cams, wherein the secondary shaft carries two ratchet wheels,and wherein the cam pairs are oriented angularly in such a manner thatthe movements of advancement effected by the two transport mechanismswhen both are operating are out of phase by half of the duration of adriving cycle.
 5. Apparatus for advancing a medium step by stepcomprising: a drive wheel for gripping said medium and rotatable formoving said medium, a first rotatable shaft having a ratchet wheel andcoupled to said drive wheel, a second shaft adapted to be rotated andhaving a pair of cams, the bosses of said cams being angularlydisplaced, a pawl-driving lever rotatable about the axis of said firstshaft, a third shaft rotatably supported at one extremity of said pawldriving lever, a pawl mounted on said third shaft and disposed to engagethe teeth of said ratchet wheel, a first cam follower member mounted onsaid third shaft and urged to follow one of said cams, whereby said pawlis controlled to cyclically engage the teeth of said ratchet wheel, anda second cam follower member mounted to drive said pawl-driving leverand urged to follow the other one of said cams, whereby said pawl iscontrolled to reciprocate along the periphery of said ratchet wheel. 6.The apparatus of claim 5 further including an electromagnet memberselectively energizable for attracting said pawl from engagement withsaid ratchet wheel.
 7. A mechanism employed with step-by-step documenttransport equipment comprising in combination: a pair of cams adapted tobe rotated, the bosses of said cams being angularly displaced, a wheelhaving teeth uniformly disposed along the periphery thereof, a shaftmounted for rotation, a pawl mounted on said shaft and disposed toengage the teeth of said wheel, a first cam follower member mounted onsaid shaft and urged to follow one of said cams, whereby said shaft iscontrolled to oscillate about the axis thereof and thereby actuate saidpawl to cyclically engage the teeth of said wheel, and a second camfollower member coupled to said shaft and urged to follow the other oneof said Cams, whereby said shaft is controlled to oscillate transverselyto said axis thereof, and thereby actuate said pawl to reciprocate alongthe periphery of said wheel.
 8. The mechanism of claim 7 furtherincluding an electromagnet member selectively energizable for attractingsaid pawl away from engagement with said ratchet wheel.